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Introduction to raw materials for producing high-strength bolts

We distinguish low carbon steel, medium carbon steel, high carbon steel and alloy steel according to the carbon content in carbon steel.

1 Low carbon steel C% ≤ 0.25% is generally called A3 steel in China. It is basically called 10081015181022 abroad. It is mainly used for Grade 4.8 bolts, Gr4 nuts, small screws and other products without hardness requirements. (Note: 1022 material is mainly used for drilling nails.)  This material is not suitable for high strength bolts.

2.Medium carbon steel >0.25%, C1035 35#, 35ACR, it is for Grade 8.8 hex bolts sizes, but for big sizes and hot forged sizes, it can’t be used.

3 High carbon steel C%>0.45%. Normally ,this steel is for Gr8.8 bolts, hot forged sizes.

4 Alloy steel: alloy elements are added to plain carbon steel to increase some special properties of steel, such as 40Cr, 35CrMo, 42CrMo., SCM435, 10B38. Fangsheng screws are mainly made of SCM435 chrome molybdenum alloy steel, mainly composed of C, Si, Mn, P, S, Cr and Mo. Our company use 40Cr or 35CrMo to proudce 10.9 bolts,  42CrMo, SCM435 to produce Gr12.9 bolts.

If the factory uses the wrong raw materials, they will fail to achieve the desired grade in the process of heat treatment, and the quality will be unqualified
Ningbo Zhongli bolts manufacturing co.ltd was set up in 2003, which is professional bolts supplier in China. It has strong techincal and production teams during last many years,Quality is excellect and stable, it mainly products are high strength DIN and ANSI standard high bolts, Hex nuts, plain washers.


Post time: Oct-27-2022